1. Field of the Invention
The invention relates to an arrangement on a component of a motor vehicle, having a sensor with a substantially planar end surface, a sealing ring enclosing the sensor, and a support element for maintaining the spacing of the sensor in the axial direction relative to the component, whereby the sensor with the sealing ring extends into a cutout of the component in such a way that the end surface of the sensor substantially forms a plane with an outer surface of the component.
2. Description of the Background Art
It is known to arrange sensors in an outer shell of a vehicle. The surroundings are detected with such sensors and objects or obstacles are identified. For example, such sensors can be ultrasonic sensors, which are used for parking assist systems.
Such sensors are acoustically decoupled by a decoupling part from the component or the structure in which they are mounted, so that arising vibrations are not transmitted from the sensor to the component and from the component to the sensor. In addition a seal should be provided between the sensor and the component to prevent the entry of a liquid, normally water, into the cutout of the component. In most cases, these sensors have a circular cross section and the decoupling or sealing parts a ring-shaped cross section. Known solutions use a so-called decoupling ring to achieve both goals.
Ultrasonic sensors send out ultrasonic signals, which are reflected from an object or obstacle located within the transmission area and are received by the same or other ultrasonic transducers. It is important for this reason that the diaphragm on the end surface of the sensor can oscillate freely. Therefore, a ring-shaped decoupling part is used to isolate the diaphragm acoustically from the installation surroundings—the component. In the case of an undesirable acoustic coupling between the sensor and component, the sensor no longer fulfills its function correctly and the coupled-in sound can again excite the diaphragm or be radiated backwards into the component. Such a situation can occur when water that has penetrated has frozen and forms an acoustic bridge. This can have the result that received vibrations are detected erroneously.
DE 100 39 060 A1 discloses an arrangement with a decoupling ring and a sealing ring with a conical axial cross section. It is a disadvantage in this regard that tolerances can arise between the diameter of the cutout in the component and the sealing ring. A consequence of these differences in cross section between the cutout in the component and the sealing ring is that water can penetrate between the sealing ring and the cutout. This can occur particularly in car wash facilities.
Decoupling rings are known, moreover, which have a circumferential bead. In the case of these decoupling rings, it can happen, as described above, that water entering under pressure cannot drain off rapidly enough and can freeze at low temperatures and thereby can reduce the action of the decoupling ring, because the solid ice can produce an acoustic connection between the sensor and component, as a result of which undesirable vibrations are transmitted between the sensor and the component.
If the sealing ring with a circumferential bead is acted on by pressurized water, the striking water can penetrate between the component and sealing ring. The remaining water can rapidly freeze and result in a decoupling of the emitted sound in the installation surroundings, for example, the bumper of the vehicle. The sensor is disrupted by this and the detection of phantom obstacles can result.